Corneal Refractive Therapy

Discover a safe, reversible alternative to laser eye surgery.

Say goodbye to wearing glasses or contact lenses during the day with overnight corneal refractive therapy.

This safe, effective, non-surgical process reshapes your cornea while you sleep so that when you awake you can enjoy clear, comfortable, 20/20 vision all day long!

  • At less than 1/3 of the cost of laser eye surgery, CRT is an affordable, safe and painless alternative to wearing glasses and contact lenses during the day.

It’s a brilliant alternative to laser surgery for people who like to play sport and find it a hassle wearing glasses or contact lenses. Or for those who work in dry or dusty environments where regular contact lenses can be difficult to tolerate. There’s even an increasing body of evidence to suggest that CRT can slow or halt the progression of myopia (short sightedness) in children.

  • Vision correction without laser surgery
  • Overcomes short sightedness
  • Safe and painless
  • Effective for all ages
  • More affordable than laser eye surgery
  • Ideal for people who do water sports

Corneal Refractive Therapy or (CRT) involves wearing specially shaped contact lenses that gently reshape the corneal surface during sleep. Upon waking, the contact lenses are removed and the reshaped cornea gives you clear, corrected vision the whole of the following day and sometimes even longer.

The reshaping effect takes about a week to reach its full effect, although there is generally a large improvement after the first night of wear. If the contact lenses are not worn for several nights then the elastic corneal tissue reverts back to its original shape – making the process completely reversible.

Corneal Refractive Therapy is also known as Corneal Reshaping Therapy, Ortho-K and Orthokeratology.

Current technology caters for low to moderate prescriptions but new lens designs are extending this range all the time. Depending on your original eye shape, we can offer CRT for prescriptions of up to -6.00 of myopia and -1.75 dioptres of astigmatism. And it’s available to people of any age!

What’s involved in having Corneal Refractive Therapy?

  1. Initial Assessment – Here we will accurately map the shape of your eye, measure your prescription and do a thorough ocular health evaluation to determine your suitability for CRT. This generally takes around 45 minutes.
  2. Overnight Trial – Ortho-K lenses are designed and fitted to your eyes for an overnight trial. We than measure your eye’s response to one night’s wear, which is an excellent indicator of success. Allow for 2 half hour appointments – one late afternoon and one the following morning.
  3. Final lens design, supply and aftercare – Following a successful two week trial, a further evaluation is done and the final lens is calculated, designed and prescribed. Close follow up in this initial phase and 12 months aftercare ensures that any issues you may have are quickly resolved and that your lenses remain comfortable and effective.

This diagram shows the redistribution of curvature over the surface that causes the power change of the eye.  It is this curvature change that allows us to dial up what we need by carefully controlling the contact lens geometry we can manipulate the pressure gradients in the tearfilm underneath the lens to curve the shape to ge the required change in optical prescription.


The following diagram shows the actual flattening of the front of the eye.  The black circle in the middle is the pupil position.  The red is the zone of maximum curvature.


At less than 1/3 of the cost of laser eye surgery, CRT is an affordable, safe and painless alternative to wearing glasses and contact lenses during the day.